[patch for 2.6.29? 1/1] acer-wmi: fix regression in backlight detection

[patch for 2.6.29? 1/1] acer-wmi: fix regression in backlight detection

[akpm]

From: Michael Spang <mspang@csclub.uwaterloo.ca>

Currently we disable the Acer WMI backlight device if there is no ACPI
backlight device.  As a result, we end up with no backlight device at all.
 We should instead disable it if there is an ACPI device, as the other
laptop drivers do.  This regression was introduced in febf2d9 ("Acer-WMI:
fingers off backlight if video.ko is serving this functionality").

Each laptop driver with backlight support got a similar change around
febf2d9.  The changes to the other drivers look correct; see e.g. 
a598c82f for a similar but correct change.  The regression is also in
2.6.28.

Signed-off-by: Michael Spang <mspang@csclub.uwaterloo.ca>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Carlos Corbacho <carlos@strangeworlds.co.uk>
Cc: Len Brown <len.brown@intel.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: <stable@kernel.org>		[2.6.28.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/platform/x86/acer-wmi.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN drivers/platform/x86/acer-wmi.c~acer-wmi-fix-regression-in-backlight-detection drivers/platform/x86/acer-wmi.c
--- a/drivers/platform/x86/acer-wmi.c~acer-wmi-fix-regression-in-backlight-detection
+++ a/drivers/platform/x86/acer-wmi.c
@@ -1297,7 +1297,7 @@ static int __init acer_wmi_init(void)
 
 	set_quirks();
 
-	if (!acpi_video_backlight_support() && has_cap(ACER_CAP_BRIGHTNESS)) {
+	if (acpi_video_backlight_support() && has_cap(ACER_CAP_BRIGHTNESS)) {
 		interface->capability &= ~ACER_CAP_BRIGHTNESS;
 		printk(ACER_INFO "Brightness must be controlled by "
 		       "generic video driver\n");
_

Re: [patch for 2.6.29? 1/1] acer-wmi: fix regression in backlight detection

[Thomas Renninger]

Hi,

On Wednesday 04 March 2009 21:07:34 akpm@linux-foundation.org wrote:
> From: Michael Spang <mspang@csclub.uwaterloo.ca>
> 
> Currently we disable the Acer WMI backlight device if there is no ACPI
> backlight device.  As a result, we end up with no backlight device at all.
>  We should instead disable it if there is an ACPI device, as the other
> laptop drivers do.  This regression was introduced in febf2d9 ("Acer-WMI:
> fingers off backlight if video.ko is serving this functionality").
> 
> Each laptop driver with backlight support got a similar change around
> febf2d9.  The changes to the other drivers look correct; see e.g. 
> a598c82f for a similar but correct change.  The regression is also in
> 2.6.28.
Len, can you apply this one, please.

> Signed-off-by: Michael Spang <mspang@csclub.uwaterloo.ca>
> Cc: Thomas Renninger <trenn@suse.de>
Signed-off-by: Thomas Renninger <trenn@suse.de>

No idea about stable policy, whether you have to wait for a mainline commit
first or if you just push such typos. Here is the patch against 2.6.28,
there the bug got introduced (file moved).

Thanks,

     Thomas

---
 drivers/misc/acer-wmi.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6/drivers/misc/acer-wmi.c
===================================================================
--- linux-2.6.orig/drivers/misc/acer-wmi.c
+++ linux-2.6/drivers/misc/acer-wmi.c
@@ -1297,7 +1297,7 @@ static int __init acer_wmi_init(void)
 
 	set_quirks();
 
-	if (!acpi_video_backlight_support() && has_cap(ACER_CAP_BRIGHTNESS)) {
+	if (acpi_video_backlight_support() && has_cap(ACER_CAP_BRIGHTNESS)) {
 		interface->capability &= ~ACER_CAP_BRIGHTNESS;
 		printk(ACER_INFO "Brightness must be controlled by "
 		       "generic video driver\n");
\0

Re: [patch for 2.6.29? 1/1] acer-wmi: fix regression in backlight detection

[Len Brown]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 2136 bytes --]

Linus checked this into 2.6.29
1ba869ec581fd9078b684c56c399ffe3d2345e27

and greg has it in his 2.6.28.stable queue,
so we're all set.

thanks,
Len Brown, Intel Open Source Technology Center

On Thu, 5 Mar 2009, Thomas Renninger wrote:

> Hi,
> 
> On Wednesday 04 March 2009 21:07:34 akpm@linux-foundation.org wrote:
> > From: Michael Spang <mspang@csclub.uwaterloo.ca>
> > 
> > Currently we disable the Acer WMI backlight device if there is no ACPI
> > backlight device.  As a result, we end up with no backlight device at all.
> >  We should instead disable it if there is an ACPI device, as the other
> > laptop drivers do.  This regression was introduced in febf2d9 ("Acer-WMI:
> > fingers off backlight if video.ko is serving this functionality").
> > 
> > Each laptop driver with backlight support got a similar change around
> > febf2d9.  The changes to the other drivers look correct; see e.g. 
> > a598c82f for a similar but correct change.  The regression is also in
> > 2.6.28.
> Len, can you apply this one, please.
> 
> > Signed-off-by: Michael Spang <mspang@csclub.uwaterloo.ca>
> > Cc: Thomas Renninger <trenn@suse.de>
> Signed-off-by: Thomas Renninger <trenn@suse.de>
> 
> No idea about stable policy, whether you have to wait for a mainline commit
> first or if you just push such typos. Here is the patch against 2.6.28,
> there the bug got introduced (file moved).
> 
> Thanks,
> 
>      Thomas
> 
> ---
>  drivers/misc/acer-wmi.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Index: linux-2.6/drivers/misc/acer-wmi.c
> ===================================================================
> --- linux-2.6.orig/drivers/misc/acer-wmi.c
> +++ linux-2.6/drivers/misc/acer-wmi.c
> @@ -1297,7 +1297,7 @@ static int __init acer_wmi_init(void)
>  
>  	set_quirks();
>  
> -	if (!acpi_video_backlight_support() && has_cap(ACER_CAP_BRIGHTNESS)) {
> +	if (acpi_video_backlight_support() && has_cap(ACER_CAP_BRIGHTNESS)) {
>  		interface->capability &= ~ACER_CAP_BRIGHTNESS;
>  		printk(ACER_INFO "Brightness must be controlled by "
>  		       "generic video driver\n");
> --8323328-524342686-1237267062=:4473--